How one gambles if one must: Effects of differing return rates on multistage betting decisions

In the multistage betting game (MBG), a decision maker (DM) is provided with some capital x which he is required to bet over m (m > 1) mutually exclusive and collectively exhaustive alternatives, each of which occurs with probability p_i (p_i > 0, i = 1,…, m; Σ_{i = 1}^mp_i = 1). If y_i is bet on alternative i (y_i ≥ 0, Σ_{i = 1}^my_i = x) and alternative i obtains, the DM's capital for the next stage is y_ir_i, (r_i > 0). The MBG lasts until either the DM loses his capital or N stages elapse, whichever comes first. Each of six subjects participated in six sessions consisting of several hundred 3-alternative MBG stages. A within-subject design assigned negative expected value (EV) bets to the first three sessions and positive EV bets to three more sessions. Significant effects were found due to return rate, capital size, homogeneous runs of either wins or losses, and individual differences. Four maximization of expected utility and two minimization of risk models were presented and tested. A modified logarithmic utility model is proposed, which provides the best fit to the data. The implications of the results and directions for further research are briefly discussed.     

Sex differences in graduate student ambition: Do men publish while women perish?

This paper compares men and women graduate students at one university and identifies conditions under which women students equal or surpass men in ambition. Men and women were broadly similar in background characteristics, though different in current family status. They studied different subjects, aimed for different degrees, and were concentrated in different years in the university. If women were to equal the most highly ambitious men on ambition to publish and engage in related behaviors, they had to aspire to a doctorate, survive past the second year of study, and have nontraditional attitudes toward women's role. The results are discussed in terms of differential student careers and barriers to the development of ambition in student women.The research upon which this paper is based was carried out with the assistance of a Lena Lake Forrest Fellowship from the Business and Professional Women's Foundation, Washington, D.C.The author wishes to thank G. L. Millerson and C. T. Husbands for comments on the draft, and Beryl Collins and Bryn Saunders for help with the typing.     

The effect of environment on visual cliff performance in the Mongolian gerbil

Depth perception in the Mongolian gerbil was investigated as a function of age and environment. Thirty-two gerbils were raised in either a cliff or flat environment, and half the gerbils in each condition were tested on the visual cliff from 21 to 57 days of age. All gerbils were tested at 60–61 days on a standard visual cliff, a barrier cliff which prevented movement along the centerboard, and a jumping platform. While the gerbils did not display a preference for the shallow side when tested at 21 days, those living in a cliff environment showed rapid acquisition of such a preference, whereas those living in a flat environment did not. By 60–61 days, however, all gerbils demonstrated a strong preference for the shallow side on both versions of the visual cliff, regardless of environment or pretesting experience.     

Specificity and savings of behavioural habituation over a series of intra- and inter-modal stimuli

A series of four tone stimuli, differing either in tonal frequency or in melody, was presented at the rate of one presentation per day to a group of rats. Habituation was specific to the frequency of simple auditory stimuli and to the melody of patterned stimuli, as shown both by the distraction to stimulus change, and by the trials to habituate to the new stimulus. Savings in habituation occurred when a series of tone stimuli was presented, but was not found for a series of inter-modal stimuli.     

Shifts in deprivation level: Different effects depending on amount of preshift training

Seventy-two male albino rats were trained to perform an instrumental running response, half at high deprivation and half at low. At Trials 23, 75, and 105 a third of the animals from each of the original groups were shifted to the opposite deprivation level. All shifts from high to low deprivation produced a significant decrease in performance; all shifts from low to high, a significant increase. After the early shift, performance was characterized by a residual effect of preshift deprivation level in which shifted groups gradually approached the new levels. After each of the later shifts, performance levels diverged sharply in what appeared to be both positive and negative contrast effects. The results were discussed in the framework of incentive motivation theory.